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<FONT color="green">001</FONT>    /*<a name="line.1"></a>
<FONT color="green">002</FONT>     * Licensed to the Apache Software Foundation (ASF) under one or more<a name="line.2"></a>
<FONT color="green">003</FONT>     * contributor license agreements.  See the NOTICE file distributed with<a name="line.3"></a>
<FONT color="green">004</FONT>     * this work for additional information regarding copyright ownership.<a name="line.4"></a>
<FONT color="green">005</FONT>     * The ASF licenses this file to You under the Apache License, Version 2.0<a name="line.5"></a>
<FONT color="green">006</FONT>     * (the "License"); you may not use this file except in compliance with<a name="line.6"></a>
<FONT color="green">007</FONT>     * the License.  You may obtain a copy of the License at<a name="line.7"></a>
<FONT color="green">008</FONT>     *<a name="line.8"></a>
<FONT color="green">009</FONT>     *      http://www.apache.org/licenses/LICENSE-2.0<a name="line.9"></a>
<FONT color="green">010</FONT>     *<a name="line.10"></a>
<FONT color="green">011</FONT>     * Unless required by applicable law or agreed to in writing, software<a name="line.11"></a>
<FONT color="green">012</FONT>     * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.12"></a>
<FONT color="green">013</FONT>     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.13"></a>
<FONT color="green">014</FONT>     * See the License for the specific language governing permissions and<a name="line.14"></a>
<FONT color="green">015</FONT>     * limitations under the License.<a name="line.15"></a>
<FONT color="green">016</FONT>     */<a name="line.16"></a>
<FONT color="green">017</FONT>    package org.apache.commons.math3.genetics;<a name="line.17"></a>
<FONT color="green">018</FONT>    <a name="line.18"></a>
<FONT color="green">019</FONT>    import java.util.ArrayList;<a name="line.19"></a>
<FONT color="green">020</FONT>    import java.util.List;<a name="line.20"></a>
<FONT color="green">021</FONT>    <a name="line.21"></a>
<FONT color="green">022</FONT>    import org.apache.commons.math3.exception.DimensionMismatchException;<a name="line.22"></a>
<FONT color="green">023</FONT>    import org.apache.commons.math3.exception.MathIllegalArgumentException;<a name="line.23"></a>
<FONT color="green">024</FONT>    import org.apache.commons.math3.exception.OutOfRangeException;<a name="line.24"></a>
<FONT color="green">025</FONT>    import org.apache.commons.math3.exception.util.LocalizedFormats;<a name="line.25"></a>
<FONT color="green">026</FONT>    import org.apache.commons.math3.random.RandomGenerator;<a name="line.26"></a>
<FONT color="green">027</FONT>    <a name="line.27"></a>
<FONT color="green">028</FONT>    /**<a name="line.28"></a>
<FONT color="green">029</FONT>     * Perform Uniform Crossover [UX] on the specified chromosomes. A fixed mixing<a name="line.29"></a>
<FONT color="green">030</FONT>     * ratio is used to combine genes from the first and second parents, e.g. using a<a name="line.30"></a>
<FONT color="green">031</FONT>     * ratio of 0.5 would result in approximately 50% of genes coming from each<a name="line.31"></a>
<FONT color="green">032</FONT>     * parent. This is typically a poor method of crossover, but empirical evidence<a name="line.32"></a>
<FONT color="green">033</FONT>     * suggests that it is more exploratory and results in a larger part of the<a name="line.33"></a>
<FONT color="green">034</FONT>     * problem space being searched.<a name="line.34"></a>
<FONT color="green">035</FONT>     * &lt;p&gt;<a name="line.35"></a>
<FONT color="green">036</FONT>     * This crossover policy evaluates each gene of the parent chromosomes by chosing a<a name="line.36"></a>
<FONT color="green">037</FONT>     * uniform random number {@code p} in the range [0, 1]. If {@code p} &amp;lt; {@code ratio},<a name="line.37"></a>
<FONT color="green">038</FONT>     * the parent genes are swapped. This means with a ratio of 0.7, 30% of the genes from the<a name="line.38"></a>
<FONT color="green">039</FONT>     * first parent and 70% from the second parent will be selected for the first offspring (and<a name="line.39"></a>
<FONT color="green">040</FONT>     * vice versa for the second offspring).<a name="line.40"></a>
<FONT color="green">041</FONT>     * &lt;p&gt;<a name="line.41"></a>
<FONT color="green">042</FONT>     * This policy works only on {@link AbstractListChromosome}, and therefore it<a name="line.42"></a>
<FONT color="green">043</FONT>     * is parameterized by T. Moreover, the chromosomes must have same lengths.<a name="line.43"></a>
<FONT color="green">044</FONT>     *<a name="line.44"></a>
<FONT color="green">045</FONT>     * @see &lt;a href="http://en.wikipedia.org/wiki/Crossover_%28genetic_algorithm%29"&gt;Crossover techniques (Wikipedia)&lt;/a&gt;<a name="line.45"></a>
<FONT color="green">046</FONT>     * @see &lt;a href="http://www.obitko.com/tutorials/genetic-algorithms/crossover-mutation.php"&gt;Crossover (Obitko.com)&lt;/a&gt;<a name="line.46"></a>
<FONT color="green">047</FONT>     * @see &lt;a href="http://www.tomaszgwiazda.com/uniformX.htm"&gt;Uniform crossover&lt;/a&gt;<a name="line.47"></a>
<FONT color="green">048</FONT>     * @param &lt;T&gt; generic type of the {@link AbstractListChromosome}s for crossover<a name="line.48"></a>
<FONT color="green">049</FONT>     * @since 3.1<a name="line.49"></a>
<FONT color="green">050</FONT>     * @version $Id: UniformCrossover.java 1385297 2012-09-16 16:05:57Z tn $<a name="line.50"></a>
<FONT color="green">051</FONT>     */<a name="line.51"></a>
<FONT color="green">052</FONT>    public class UniformCrossover&lt;T&gt; implements CrossoverPolicy {<a name="line.52"></a>
<FONT color="green">053</FONT>    <a name="line.53"></a>
<FONT color="green">054</FONT>        /** The mixing ratio. */<a name="line.54"></a>
<FONT color="green">055</FONT>        private final double ratio;<a name="line.55"></a>
<FONT color="green">056</FONT>    <a name="line.56"></a>
<FONT color="green">057</FONT>        /**<a name="line.57"></a>
<FONT color="green">058</FONT>         * Creates a new {@link UniformCrossover} policy using the given mixing ratio.<a name="line.58"></a>
<FONT color="green">059</FONT>         *<a name="line.59"></a>
<FONT color="green">060</FONT>         * @param ratio the mixing ratio<a name="line.60"></a>
<FONT color="green">061</FONT>         * @throws OutOfRangeException if the mixing ratio is outside the [0, 1] range<a name="line.61"></a>
<FONT color="green">062</FONT>         */<a name="line.62"></a>
<FONT color="green">063</FONT>        public UniformCrossover(final double ratio) throws OutOfRangeException {<a name="line.63"></a>
<FONT color="green">064</FONT>            if (ratio &lt; 0.0d || ratio &gt; 1.0d) {<a name="line.64"></a>
<FONT color="green">065</FONT>                throw new OutOfRangeException(LocalizedFormats.CROSSOVER_RATE, ratio, 0.0d, 1.0d);<a name="line.65"></a>
<FONT color="green">066</FONT>            }<a name="line.66"></a>
<FONT color="green">067</FONT>            this.ratio = ratio;<a name="line.67"></a>
<FONT color="green">068</FONT>        }<a name="line.68"></a>
<FONT color="green">069</FONT>    <a name="line.69"></a>
<FONT color="green">070</FONT>        /**<a name="line.70"></a>
<FONT color="green">071</FONT>         * Returns the mixing ratio used by this {@link CrossoverPolicy}.<a name="line.71"></a>
<FONT color="green">072</FONT>         *<a name="line.72"></a>
<FONT color="green">073</FONT>         * @return the mixing ratio<a name="line.73"></a>
<FONT color="green">074</FONT>         */<a name="line.74"></a>
<FONT color="green">075</FONT>        public double getRatio() {<a name="line.75"></a>
<FONT color="green">076</FONT>            return ratio;<a name="line.76"></a>
<FONT color="green">077</FONT>        }<a name="line.77"></a>
<FONT color="green">078</FONT>    <a name="line.78"></a>
<FONT color="green">079</FONT>        /**<a name="line.79"></a>
<FONT color="green">080</FONT>         * {@inheritDoc}<a name="line.80"></a>
<FONT color="green">081</FONT>         *<a name="line.81"></a>
<FONT color="green">082</FONT>         * @throws MathIllegalArgumentException iff one of the chromosomes is<a name="line.82"></a>
<FONT color="green">083</FONT>         *   not an instance of {@link AbstractListChromosome}<a name="line.83"></a>
<FONT color="green">084</FONT>         * @throws DimensionMismatchException if the length of the two chromosomes is different<a name="line.84"></a>
<FONT color="green">085</FONT>         */<a name="line.85"></a>
<FONT color="green">086</FONT>        @SuppressWarnings("unchecked")<a name="line.86"></a>
<FONT color="green">087</FONT>        public ChromosomePair crossover(final Chromosome first, final Chromosome second)<a name="line.87"></a>
<FONT color="green">088</FONT>            throws DimensionMismatchException, MathIllegalArgumentException {<a name="line.88"></a>
<FONT color="green">089</FONT>    <a name="line.89"></a>
<FONT color="green">090</FONT>            if (!(first instanceof AbstractListChromosome&lt;?&gt; &amp;&amp; second instanceof AbstractListChromosome&lt;?&gt;)) {<a name="line.90"></a>
<FONT color="green">091</FONT>                throw new MathIllegalArgumentException(LocalizedFormats.INVALID_FIXED_LENGTH_CHROMOSOME);<a name="line.91"></a>
<FONT color="green">092</FONT>            }<a name="line.92"></a>
<FONT color="green">093</FONT>            return mate((AbstractListChromosome&lt;T&gt;) first, (AbstractListChromosome&lt;T&gt;) second);<a name="line.93"></a>
<FONT color="green">094</FONT>        }<a name="line.94"></a>
<FONT color="green">095</FONT>    <a name="line.95"></a>
<FONT color="green">096</FONT>        /**<a name="line.96"></a>
<FONT color="green">097</FONT>         * Helper for {@link #crossover(Chromosome, Chromosome)}. Performs the actual crossover.<a name="line.97"></a>
<FONT color="green">098</FONT>         *<a name="line.98"></a>
<FONT color="green">099</FONT>         * @param first the first chromosome<a name="line.99"></a>
<FONT color="green">100</FONT>         * @param second the second chromosome<a name="line.100"></a>
<FONT color="green">101</FONT>         * @return the pair of new chromosomes that resulted from the crossover<a name="line.101"></a>
<FONT color="green">102</FONT>         * @throws DimensionMismatchException if the length of the two chromosomes is different<a name="line.102"></a>
<FONT color="green">103</FONT>         */<a name="line.103"></a>
<FONT color="green">104</FONT>        private ChromosomePair mate(final AbstractListChromosome&lt;T&gt; first,<a name="line.104"></a>
<FONT color="green">105</FONT>                                    final AbstractListChromosome&lt;T&gt; second) throws DimensionMismatchException {<a name="line.105"></a>
<FONT color="green">106</FONT>            final int length = first.getLength();<a name="line.106"></a>
<FONT color="green">107</FONT>            if (length != second.getLength()) {<a name="line.107"></a>
<FONT color="green">108</FONT>                throw new DimensionMismatchException(second.getLength(), length);<a name="line.108"></a>
<FONT color="green">109</FONT>            }<a name="line.109"></a>
<FONT color="green">110</FONT>    <a name="line.110"></a>
<FONT color="green">111</FONT>            // array representations of the parents<a name="line.111"></a>
<FONT color="green">112</FONT>            final List&lt;T&gt; parent1Rep = first.getRepresentation();<a name="line.112"></a>
<FONT color="green">113</FONT>            final List&lt;T&gt; parent2Rep = second.getRepresentation();<a name="line.113"></a>
<FONT color="green">114</FONT>            // and of the children<a name="line.114"></a>
<FONT color="green">115</FONT>            final List&lt;T&gt; child1Rep = new ArrayList&lt;T&gt;(first.getLength());<a name="line.115"></a>
<FONT color="green">116</FONT>            final List&lt;T&gt; child2Rep = new ArrayList&lt;T&gt;(second.getLength());<a name="line.116"></a>
<FONT color="green">117</FONT>    <a name="line.117"></a>
<FONT color="green">118</FONT>            final RandomGenerator random = GeneticAlgorithm.getRandomGenerator();<a name="line.118"></a>
<FONT color="green">119</FONT>    <a name="line.119"></a>
<FONT color="green">120</FONT>            for (int index = 0; index &lt; length; index++) {<a name="line.120"></a>
<FONT color="green">121</FONT>    <a name="line.121"></a>
<FONT color="green">122</FONT>                if (random.nextDouble() &lt; ratio) {<a name="line.122"></a>
<FONT color="green">123</FONT>                    // swap the bits -&gt; take other parent<a name="line.123"></a>
<FONT color="green">124</FONT>                    child1Rep.add(parent2Rep.get(index));<a name="line.124"></a>
<FONT color="green">125</FONT>                    child2Rep.add(parent1Rep.get(index));<a name="line.125"></a>
<FONT color="green">126</FONT>                } else {<a name="line.126"></a>
<FONT color="green">127</FONT>                    child1Rep.add(parent1Rep.get(index));<a name="line.127"></a>
<FONT color="green">128</FONT>                    child2Rep.add(parent2Rep.get(index));<a name="line.128"></a>
<FONT color="green">129</FONT>                }<a name="line.129"></a>
<FONT color="green">130</FONT>            }<a name="line.130"></a>
<FONT color="green">131</FONT>    <a name="line.131"></a>
<FONT color="green">132</FONT>            return new ChromosomePair(first.newFixedLengthChromosome(child1Rep),<a name="line.132"></a>
<FONT color="green">133</FONT>                                      second.newFixedLengthChromosome(child2Rep));<a name="line.133"></a>
<FONT color="green">134</FONT>        }<a name="line.134"></a>
<FONT color="green">135</FONT>    }<a name="line.135"></a>




























































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